This proposal will provide the applicant, Chia Wang, with training in the epidemiologic study of viral transmission. Dr. Wang is a board certified ID physician with a MS in Epidemiology. During her fellowship at the University of Washington, she studied heterosexual HIV transmission in Africa. This project formed the foundation of a long term interest in the epidemiology of transmission and acquisition of infection. This proposal describes her research interests in the area of non-parenteral transmission of hepatitis C virus (HCV). [unreadable] In Aim 1, we will study individuals with chronic infection in a longitudinal study of the prevalence and pattern of shedding of HCV RNA in saliva and genital tract fluids. Furthermore, information about oral and genital tract inflammatory conditions will be collected to investigate the hypothesis that such conditions may increase shedding. In Aim 2, we explore the hypothesis that transmission may occur more efficiently during the acute phases of HCV infection. We will establish early serum viral load dynamics and mucosal shedding patterns in incident cases of HCV identified from a local cohort of HCV negative current IDUs. Finally, in Aim 3, we will examine potential risk factors in individuals who deny parenteral modes of transmission by incorporating audio computer-assisted survey instrument (ACASI) technology to reduce under-reporting bias and specific survey techniques to reduce recall bias. The under-reporting rate of stigmatized behaviors such as intravenous drug use will be determined in subjects who deny such risk factors in traditional face-to-face interviews. Reporting of other potential non-parenteral risk factors for hepatitis C, such as intranasal cocaine use, will be compared to that of a control population derived from general medicine clinic. The mode of infection in 20-30% of hepatitis C-infected individuals remains poorly understood. The findings of the proposed research study may confirm suspected transmission routes such as sexual exposure, or may refute current figures suggesting that a substantial proportion of infections may occur non- parenterally. In addition, the proposed project will provide Dr. Wang with training in viral transmission research beyond her rather focused fellowship project, with the goal of establishing her expertise in this field and providing her with skills to pursue further independent studies in the transmission of hepatitis C and other viruses. [unreadable] [unreadable]